1. Field of the Invention
The present invention generally relates to a semiconductor device, and more specifically, to a chip scale semiconductor package having a ball grid array (BGA) provided with through-holes for dispensing liquid encapsulant.
2. Description of the Related Art
Ball grid array-(hereinafter "BGA") type semiconductor package is typically designed to provide high signal inputs and outputs (I/O). A BGA-type package is suitable for the packaging of ultra-large-scale integration (ULSI) integrated circuits made in submicron scale. A BGA-type package is the preferred choice for packaging of high I/Os chips.
A BGA-type package is typically constructed with a BGA substrate with a chip attached thereon. Leads of said BGA substrate are soldered to bonding pads of said chip. In the encapsulation process, an encapsulant is dispensed onto the bonding area of said BGA substrate and then the encapsulant is cured by heating. Then, said BGA substrate is turned so that the chip mounting surface faces up, and encapsulant is dispensed onto the area around the edge of said chip said encapsulant is cured by heating. However, dispensing and curing have to be repeated twices. Thus, the whole encapsulation process is time-consuming thereby decreasing the throughput rate.
FIG. 1 illustrates the die-attaching process of a conventional BGA-type package. As shown in FIG. 1, a substrate 110 is attached onto a semiconductor die 100 by an adhesive layer 102 in such a manner that bonding pads 101 of said die 100 are exposed within a through-hole 103 of said substrate 110, which defines a first encapsulation area 114. Said substrate 110 comprises a copper foil layer 111 and a polymer layer 113. The copper foil layer 111 is provided with a plurality of leads 112 located within the first encapsulation area 114 for soldering to the bonding pads 101 of said die 100. The polymer layer 113 is further provided with a plurality of holes (not shown) for mounting solder balls in such a manner that said solder balls are connected to said copper foil layer 111 whereby said solder balls are electrically interconnected to said chip through the leads 112 of said substrate 110. The area around the edge of said die 100 is defined by a second encapsulation area 104.
FIG. 2 illustrates the lead bonding process of said conventional BGA type package. As shown in FIG. 2, the leads 112 of said substrate 110 are soldered to the bonding pads 101 of said die 100 thereby interconnecting said die 100 and said substrate 110.
FIG. 3 illustrates the first encapsulation process of said conventional BGA type package. As shown in FIG. 3, encapsulant is dispensed onto the first encapsulation area 114 by a dispenser A and then cured into a first package body 115 which encapsulates the leads 112 of said substrate 110 and the bonding pads 101 of said die 100. Said substrate 110 cannott be turned to perform the second encapsulation process until the encapsulant is cured.
FIG. 4 illustrates the second encapsulation process of said conventional BGA type package. As shown in FIG. 4, encapsulant is dispensed onto the second encapsulation area 104 by a dispenser A and then cured into a second package body 105 which encapsulates the area around the edge of said die 100. However, dispensing and curing have to be repeated twice. Therefore, the whole encapsulation process is time-consuming and thereby decreases the throughput rate.
Accordingly, the present invention is intended to mitigate and/or obviate the above problems by providing a substrate having at least a through-hole through which encapsulant can flow from the active surface of the die to the edge thereof. Therefore, the encapsulation process can be accomplished without turning the substrate thereby reducing the manufacturing time and increasing the throughput rate.